The present invention relates generally to an intravenous (IV) fluid reconstitution system that is compact, robust, and suitable for use at a site under non-clean room environment and large variations in feed water temperature and/or quality. For field applications, such a device must be not only compact and energy efficient, but also robust and easy to operate. Such a device is referred to herein as the field IV fluid reconstitution (FIVR) system.
During recent major military campaigns and emergencies, the military has encountered logistic problems in collecting, transporting, delivering, and storing units of whole fresh blood before the products become outdated. One possible solution is to develop new techniques to freeze red blood cells to increase storage life. However, reconstitution of the blood from the frozen red blood cells requires special blood washing solutions. To effect this reconstitution, sterile water for injection (SWFI) is needed to prepare the special solutions, partly negating the space-saving and shelf-life advantage of the frozen red blood cells by requiring storage of bags of SWFI that have their own finite shelf-life and logistic issues.
Deployment of IV fluids is also a logistic burden as well as a compromise for immediate medical services needed in various emergency situations. IV fluids are bulky, heavy, and lower priority to deploy by air lift. IV fluids also have limited shelf life, which can be further shortened if they are exposed to extreme environment conditions.
In addition to frozen blood reconstitution, sterile, pyrogen-free water is needed for other medical applications such as washing, irrigation, and preparation of medicated solute for intravenous injection in military or civilian emergency situations.
The SWFI system of the present invention can supply field medical operations with a steady, reliable stream of SWFI on demand and thereby simplify the logistic support of expeditionary forces, reduce the number and cost of supply flights, and liberate precious space aboard Navy ships for other mission-critical equipment and supplies. While the SWFI system was developed to support medical applications such as the production of intravenous fluids, blood washing, and clinical irrigation procedures aboard amphibious assault and hospital ships in the fleet, this technology may also find a considerable civilian market including a number of opportunities in bio-technology and pharmaceutical research laboratories, isolated medical facilities, mobile medical units, and emergency relief operations in case of natural disasters or terrorist attacks.
U.S. Pat. No. 5,484,431 (the '431 patent) by Scharf et al. discloses a system and method for creating at a site, remote from a sterile environment, a parenteral solution. However, the '431 patent primarily deals with the container having a prepackaged amount of solute, rather than the generation of SWFI. The container is constructed and arranged so that sterile water can flow through a port, then a filter, and into the container where it is mixed with the solute to create a parenteral solution that can then be infused into a patient. The only reference to a sterile water source capable of producing sterile water for injection into the '431 container is a system developed for NASA comprising a plurality of filters and beds.
Such a SWFI production system is the subject of U.S. Pat. No. 4,610,790 by Reti et al., which discloses a system for producing sterile water and sterile aqueous solutions by combination of pre-filtration, reverse osmosis, de-ionization and ultrafiltration. Other systems which produce sterile water using pre-filtration, reverse osmosis, and/or de-ionization include GB Patent Application Publication 2,002,736, by Alhauser, U.S. Pat. No. 4,881,661 by Jones and U.S. Pat. No. 6,679,988 by Gsell (the '988 patent). Further, U.S. Pat. No. 5,032,265, by Jha et al. (the '265 patent), describes a method and a system for purifying potable water to produce SWFI, wherein the water passes through a pre-filter, a carbon filter, a reverse osmosis module, a ion exchange filter, and a disposable sterilizing microfilter. U.S. Pat. No. 5,520,816, by Kuepper, discloses a zero waste effluent desalination system, using a reverse osmosis or nanofilter membrane element to desalinate water. Finally, European Patent Application No. EP 1785151 (the '151 Application) of Weatherill discloses a heat sanitization system for a reverse osmosis and filtration system. While the '988 and '265 patents and the '151 Application use a heater to heat water for purposes of sterilizing the system, each of these prior art devices fail to use heat sterilization for the production of product water (SWFI).
U.S. Pat. Nos. 6,585,890 and 6,858,179 by Li et al. disclose a compact system capable of producing, and the associated process of producing, SWFI from potable water, that could serve as a sterile water source at a site, remote from sterile environments. Specifically, the system and process disclosed comprises three phases: 1) hydrothermal processing for sterilization and depyrogenation of the potable water; 2) multi-stage flash evaporation for salt removal and heat recovery; and 3) in-situ filtration for particle removal. Similarly, U.S. Pat. No. 6,485,649, by Terava et al., teaches a method and a device for the production of sterile water, using a heat sterilizer, a pump, and a filter unit to purify the water. None of these patents include the use of de-ionization beds or reverse osmosis membranes, and therefore are unable to efficiently generate SWFI from large variations in feed water quality and temperature as a transportable system.
U.S. Pat. No. 7,122,149 (the '149 patent) by Li et al. discloses an energy efficient and compact SWFI generator that incorporates an effective process control mechanism to maintain process temperature, pressure, and water flow rate. The '149 patent specifically discloses and enables a hydrothermal processor module which is useful in the system of the present invention, and is incorporated herein by this reference.
U.S. Pat. No. 4,072,610, by Gow et al. (the '610 patent), presents a method and an apparatus for the production of sterile aqueous solutions with water and concentrate, using a pre-filter, a reverse osmosis column, a deionizer, and a heat sterilizer to create a sterilized solution of water and other, usually medicinal, fluid. Gow et al. discloses heat sterilization of the product at 150-160° C., a very high temperature range requiring substantial energy; further, the Gow invention fails to recognize the necessity for adjusting the temperature of the feed water, prior to deionization, and provides only a single feedback loop for the retentate, which may include product overflow.
Conventional technologies dealing with automatic aseptic bag filling primarily focuses on fixed facility and large equipment. For instance, U.S. Pat. No. 4,730,435 by Riddle et al. disclosed a sterile docking system for aseptically filling IV bags in non-clean room environments, whereby the sterile docking unit of the invention positions over an IV bag and directs HEPA filtered air around the nozzle and diaphragm of the bag to create a clean room environment.
Most of the prior art patents do not include means to heat the feed water prior to entering the filtration beds (except for purposes of sanitization). While, Jha et al., describes a method for pre-heating the tap water with heat from the rejected water, as well as using a heater. Jha et al. does not contemplate a heater capable of adjusting the temperature of the feed water where the initial temperature varies, nor does it contemplate cooling the feed water.
Furthermore, none of the prior art patents use a multi purpose surge tank to provide a second retentate recycle loop, capture steam and hot water from the hydrothermal processor module, and provide for bottled water input into the system. Weatherill uses a surge tank only for purposes of receiving pure water and disbursing the same during sanitization, and Gow discloses a surge tank for purposes of receiving retentate as a first feedback loop, and overflow product water which includes medical compositions.
In addition, none of these patents are designed for use in a myriad of field conditions. For example, the temperature of feed water in the field may vary significantly from just above the freezing point to temperatures encountered in a desert environment. This temperature variation could range from 33-140° F. (0.6-60° C.). However, the temperature range recommended by manufacturers of pre-filters, reverse osmosis membranes, and de-ionization resin beds typically is 45-113° F. (7-45° C.). Therefore, a temperature conditioning system is desirable to adjust feed water temperature to within a suitable temperature range when reaching the water preconditioning module.
There is also a preferred range of SWFI temperature for reconstitution of IV fluids and subsequent or immediate administration of such fluids to patients. This temperature is likely to be in the range from about 15° C. to about 55° C., preferably from about 35° C. to about 45° C. (i.e., about body temperature). The basic control and regulation of the temperature of SWFI are part of the hydrothermal fluid processor disclosed in the '149 and '610 patents which only addressed cooling the SWFI when the temperature of the feed water was near ambient conditions (i.e., about 60-80° F. (15-27° C.)) encountered in household tap water supply. Specifically, embodiments disclosed in each of these patents include a heat exchanger for heating feed water and cooling SWFI; however, the heat exchanger will only cool the SWFI to a temperature range based upon the feed water temperature. No further controls are included to modify the temperature of the SWFI to a specific temperature range regardless of the temperature of the feed water. By design, the temperature of SWFI coming out of the hydrothermal fluid processor is higher than that of the feed water. Therefore, the prior art could not provide SWFI within an acceptable temperature range if the feed water temperature is excessive (i.e., over 113° F. or 45° C.). The '151 Application contemplates mixing cold and hot tap water for injection into the system, but the only functionality described with this temperature control is that cold water is used to cool down the system after heat sterilization.
The FIVR system in which the present invention is incorporated consists of three basic component technologies: (A) an SWFI generator that produces SWFI on site and on demand from potable water or water that meets the EPA drinking water quality upon preconditioning; (B) sterilized bags pre-filled with dry chemicals or concentrate prepared for reconstitution with SWFI; and (C) a feed water temperature conditioning assembly.
The SWFI generator technology disclosed in the '149 patent presents the design basis for compact and energy efficient systems. However, the issues associated with maintenance, automation, robustness, ease of operation, variations in feed water temperature, and use of bottled water as the feed water source were not resolved by the technologies, teachings and methods of the '149 patent.
It is an object of the invention to provide an improved system for on-site and on-demand production of SWFI from potable water or water that meets the EPA drinking water quality upon preconditioning, and in conjunction with reconstitution of IV fluids using dry chemicals or concentrate pre-filled bags in a safe, expedient, and effective manner suitable for use at a non-clean room or pseudo clean room environment site and subject to large variations in feed water temperature and/or quality.
It is a further object of the invention to provide a system and method for achieving a robust and fail-safe system that can be turned off at any time, as a result of power failure or intentional or unintentional human intervention, without damaging system components or injuring operators due to high temperature steam released from the system, or releasing high temperature water.
It is another object of the invention to provide a system and method for using bottled water as the feed water to produce SWFI.
It is another object of the invention to provide a system and method for cooling feed water, including by refrigeration systems with radiator cooling devices.
It is another object of the invention to provide a system and method for producing SWFI within a desirable temperature range.
These and other objects of the invention will become apparent as a general description of the present invention and detailed description of representative embodiments proceeds.